# Regression through the origin

• Mar 25th 2009, 04:18 AM
panda
Regression through the origin
When I want to test if forcing the data to go through the origin is a good thing rather than just leaving it just the way it is, what value do i have to look at it?
for instance, there is a data that i want to fit it so that it go through the origin. Then do i have to look at the p-value of intercept or F statistics value? or what do i have to look for if i wanna test 'passing through the origin' is a good thing.

• Mar 25th 2009, 11:24 PM
matheagle
All you need to do is leave out the intercept term in your model.

Say, $Y=b_1x+b_2x^2 + \ldots +b_px^p + \epsilon$.

Now, if you're not interested in values near the origin, there's no reason to force your curve through that point.
This will affect your other parameters.
• Mar 26th 2009, 03:32 PM
Predictor
Quote:

Originally Posted by panda
When I want to test if forcing the data to go through the origin is a good thing rather than just leaving it just the way it is, what value do i have to look at it?
for instance, there is a data that i want to fit it so that it go through the origin. Then do i have to look at the p-value of intercept or F statistics value? or what do i have to look for if i wanna test 'passing through the origin' is a good thing.